But key indexes rose sharply as the day wore on. Chief economist Peter Cardillo at Avalon Partners blamed uncertainty for the market volatility.

VOA: standard.2010.07.20

With a different volatility for the stocks because that was also selected randomly, plus some market bias.

或者均匀分布的一个随机值,因为数值选择上的随机性，再加上市场偏好。

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